Automatic vapor engine start-up

ABSTRACT

An automatic start-up system for a Rankine cycle engine provides start-up from a single actuation; for example, the closing of a switch. The start-up system initiates operation of a vapor generator for vaporizing working fluid which is admitted to an expander to produce work and a pumping system which supplies working fluid in the liquid state to the vapor generator. When the vaporized working fluid from the vapor generator begins to operate the expander at a predetermined running speed, the startup system is deenergized to terminate start-up operation. The engine then continues in a running mode. The engine may have a valve between the vapor generator and the expander for controlling admission of vaporized working fluid to the expander. When such a valve is present, a control means responsive to an appropriate engine operating condition is provided for establishing the proper valve setting.

United States Patent Pezaris e t al.

AUTOMATIC VAPOR ENGINE START-UP Inventors: Constantine D. Pezaris,Nahant;

William P. Tegan, Billerica; Paul J. Tram'e, South Hamilton, all ofMass.

[73] Assignee: Thermo Electron Corporation,

Waltham, Mass. I

[22] Filed: Jan. 6, 1972 [21] Appl. No.: 215,898

52 US. Cl. 60/106, 122/406 [51] Int. Cl. F23n 1/10 [58] Field of Search60/105, 106,107, 6, 73; 122/33, 406 ST [56] I References Cited UNITEDSTATES PATENTS 702,491 6/1902 Serpollet 60/106 3.264.826 8/1966 Kane eta1... 60/73 3271960 9/1966 Brunner... 60/73 1,551,438 8/1925 Staley60/105 1.664.329 3/1928 Staley 60/105 3.172.266 3/1965 Strohmeyer 60/1053.477.412 11/1969 Kitrilakis 122/33 Primary Examiner-Edgar W. GeogheganAssistant Examiner1-I. Burks, Sr. Attorney, Agent, or Firm-James L. Neal57 ABSTRACT An automatic start-up system for a Rankine cycle engineprovides start-up from a single actuation; for example, the closing of aswitch. The start-up system initiates operation of a vapor generator forvaporizing working fluid which is admitted to an expander to pro ducework and a pumping system which supplies working fluid in the liquidstate to the vapor generator. When the vaporized working fluid from thevapor generator begins to operate the expander at a predeterminedrunning speed, the start-up system is deenergized to terminate start-upoperation. The engine then continues in a running mode. The engine mayhave a valve between the vapor generator and the expander forcontrolling admission of vaporized working fluid to the expander. Whensuch a valve is present, a control means responsive to an appropriateengine operating condition is provided for establishing the proper valvesetting.

23 Claims, 6 Drawing Figures 177 156 PS VALVE CONTROL SECTION 194 190 I184 186 PULSE 192 f I BATTERY I S M GENERAToRI I 163 s I STEPPING ooMPARToR I MoToR CIRCUIT MEANS I 102 108 LEVEL J l DETECTOR I I I I 196 1E2----v-- 193I BURNER 1 II I CONTROL V I v I SEPARATOR I I MEANS I VAPOR164 GENERATOR I 200 I I I 136 I I COMBUSTION I I #114 I I I BLOWERBuRNERI AND IGNITION I I 104 121 166 I 118 ATQMIZATION I I n I'"COMPRESSOR I 3 REGENERATOn EXPANDER I :170 I I v 122 I FUEL I /I I PUMPIVALVE l 124T 128 129 I I A71 132 I I coNoENsER RECEIVER 1as L :35: I IA.

NEG I PRESSURE VOLTAGE CONTROL I BOOST J I VAPOR GENERATOR SOURCE IVALVE PUMP [BATTERY l STARTING SECTION I I 138 PUMP 176 INHIBIT STARTINGsEcT1oN PATENIEUHARIS I974 3797249 sum 2 OF 4 VAPOR TO ENGINE WATER Iso152 146 WORKING LIQUID TO BOILER PATENTEDHAR 19 I974 SHEET 3 BF 4 Fig.3.

r Fig: 4.

AUTOMATIC VAPOR ENGINE START-UP BACKGROUND OF THE INVENTION Vaporengines of the Rankine cycle type provide a desirable power source fornumerous reasons, including the relatively low level of pollutantproduction resulting from their use. However, difficulty has beenexperienced in providing a start-up system which is dependable, easy'tooperate and economically feasible.

SUMMARY OF THE INVENTION The engine start-up system of this invention iscapable of initiating operation of the engine by a single actuation.When actuation occurs, operation according to a start-up mode begins andproduces various starting events in the proper manner and the propersequence. Essentially, the start-up system ignites a burner for a vaporgenerator while supplying working fluid in the liquid state to the vaporgenerator. In the vapor generator, the working fluid is evaporated,brought to an appropriately elevated temperature and is usuallysuperheated. Vapor from the vapor generator is admitted to an expanderto produce work from expansion of the vaporized working fluid. Whenexpander. operation reaches a predetermined operating speed, operationaccording to the start-up mode is terminated and operation continues inthe running mode.

Vapor generator and pumping system operation may be initiatedsimultaneously or in sequence, according to the dictates of theparticular engine under consideration. It is often preferable to firstinitiate operation of the vapor generator so that it is brought to apredetermined temperature level before an appreciable amount of workingfluid in the liquid state is supplied thereto.

Vaporized working fluid from the vapor generator may be fed directly tothe expander or a valve may control its admission. In systemsincorporating such a valve, the valve would typically be closed atstart-up and remain closed until predetermined temperature and pressureconditions exist in the engine. The valve would then be opened to admitvaporized working fluid to the expander. Such operation of the valve tocontrol admission of working fluid to the expander assures that theworking fluidwhich reaches the expander will be at or near the optimumtemperature and pressure to thereby facilitate a more positive start forthe engine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing apreferred embodiment of the invention;

FIG. 2 illustrates an example of a vapor generator usable with theengine of FIG. 1;

FIG. 3 is a schematic view showing an alternate embodiment of theinvention;

FIG. 4 illustrates a typical control for the apparatus of FIG. 3; I

FIG. 5 is a schematic illustration of another embodiment of theinvention; and

FIG. 6 shows a typical control for the apparatus of FIG. 5.

DETAILED DESCRIPTION OF THE DRAWINGS Reference will now be made toFIG. 1. The Rankine cycle engine 100 incorporates a vapor generator 102and burner means 104. An outlet line 106 extends from the vaporgenerator to an oil separator 108. From the oil separator, a line 1 10extends to a throttle valve 1 12 and an oil drain 114 extends to the oilstorage zone of an expander 116. The throttle valve 112 controlsadmission of vaporized working fluid to the expander 116. The expanderexpands the vaporized working fluid to produce work. In this embodiment,the expander turns a driveshaft 119 and an alternator 117 to producealternating current. Working fluid from the expander is dischargedthrough a line 118 to the vapor side of a regenerative heat exchanger120. The vapor then passes from the regenerative heat exchanger througha line 122, to a working fluid condensing means 124. The working fluidpassing from the vapor generator to the condenser is in the vapor phase.Consequently, this portion of the engine is referred to as the vaporside. correspondingly, in the portion of the cycle from the condenserback to the vapor generator, the working fluid is in its liquid phaseand this portion of the engine is referred to as the liquid side.Liquified working fluid passes from the condenser 124 through the line128 to a receiver, or reservoir, 130. A centrifugal boost pump 131communicates with the outlet of the receiver and is capable of supplyingworking fluid from the receiver to a feed pump 132. The feed pumpdelivers working fluid, through the line 134, to the liquid side of theregenerative heat exchanger 120. The condensed working fluid is heatedin the regenerative heat exchanger and delivered through a line 136 tothe inlet of the vapor generator 102. A relief line 138 joins lines 128and 134. A pressure control valve 140 in the relief line permits a flowof working fluid back to the receiver 130 if the output of the feed pump132 is in excess of that required for operation of the engine.

This engine may employ any convenient form of vapor generator. One whichhas been found to provide good results is that described in US. Pat. No.3,477,412 which issued on Nov. 1 l, 1969 to Soti ris Kitrilakis and isassigned to the assignee of the present ap plication. A briefdescription of this vapor generator will be; given in connection withFIG. 2. a more complete explanationmay be obtained by reference to theabove designated patent.

There is provided within a housing 142 a burner 144 forming part of theburner means 104 and a coiled heat exchange tube means 146. The heatexchange tube means comprises an inner tube 148 for conducting workingfluid through the vapor generator and an outer tube 150 which surroundsthe inner tube 148 concentrically and provides a space 152 between thetubes for containing a thermally stable buffer fluid. The outer tube 150forms part of a closed buffer fluid system which includes an expansionchamber 154. The buffer fluid provides a temperature buffer between theheat source and the working fluid to avoid hot spots within the vaporgeneratorv along the tube 148. From the expansion chamber 154, there isprovided a pressure sensitive device 156 which is capable of providing asignal 158 proportional to buffer fluid pressure. Buffer fluid pressurewill, in turn, be a function of working fluid temperature. The signal158 may be fluid, electrical, or of any suitable type. The subsequentdiscussion of the signal presupposes that it is electrical.

The start-up system for the vapor engine set forth above will now bedescribed. For convenience of discussion, the start-up system may beregarded as having three basic sections. These are a vapor generatorstarting section 171, a pump starting section 173, and a valve controlsection 175.

The vapor generating starting section 171 includes a burner controlmeans 162, a combustion blower and ignition means 164, an atomizationcompressor 166, fuel pump means 168, and fuel valve means 170.

The pump starting section 173 draws electrical energy from a battery 176which constitutes an auxiliary power source. A current relay 180 andrectifier 178 provide a switchable electrical connection between thebattery 176 and the boost pump 131 and between the battery and a set ofdc windings in a manner-herafter described. The starting motor 182 turnsthe expander driveshaft 1 17. The starting motor 182 may be a separatecomponent of the dc windings or the starting motor may be incorporatedwithin the alternator 117.

The valve control section 175 comprises a stepping motor 184 and astepping motor drive circuit 186 for controlling the position of thevalve 112. The stepping motor drive circuit 186 is operated as afunction of the operating speed of the expander 116. The control means175 illustrated here by way of example is fully described and set forthin copending and coassigned U.'S. patent application Ser. No. 215,838,filed Jan. 6, 1972 in the names of Peter Teagan, Constantine Pezaris,and Paul Trame and entitled Vapor EngineSpeed Control. Briefly, thevalve control means 175 utilizes the alternator 117 as a tachometersignal from the expander 116. This signal input 188 is fed to acomparator means 190 which compares it to a reference signal,-

the reference signal being related to the desired operational speed ofthe expander 116. The output of the comparator means 190 is fed throughan adder means 192 which provides a signal input to a pulse generator194 and a level detector 196. The outputs of the pulse generator and thelevel detector are fed to the stepping motor drive 186. The pulsegenerator determines the number of pulses and thereby the distance whichthe stepping motor 184 and the valve 112 will move and the leveldetector 196 determines the direction in which the valve element 112will move in accordance with the polarity of the signal received fromthe adder 192. The throttle valve 112 is thus capable of adjustment tofully open and fully closed positions and to a full range ofintermediate positions. One example of a throttle valve suitable for usewith the valve control means 175 is described in a copending andcoassigned US. patent application Ser. 215837 filed Jan. 6, 1962 in thename of ThomasLeFeuvre and entitled Throttle Valve.

There is provided in line 134, adjacent the outlet of the feed pump 132,a pressure switch 135 for selectively admitting a negative voltagesignal 137 to the added means 192. When this signal is absent, the valvecontrol means 175 operates as described above. When present, the signal137 is of substantially greater magnitude than the adder input from thecomparator 190 and thus operates as an inhibiting signal, overridingvalve opening inputs to the pulse generator 194 and the level detector196.

OPERATION The engine first operates according to a start-up mode and,when a predetermined running speed has been reached, operation continuesaccording to a running mode.

The entire starting and running mode proceeds automatically from asingle actuation by an operator. For example, an operator may push abutton 200 to close a switch within the burner control means 162. Thepressure switch provides the inhibiting signal 137 to the adder 192. Theburner control means then simultaneously provides electrical energy tothe fuel pump 168, fuel valve 170, atomization compressor 166, and thecombustion blower and ignitor 164. The result is the energization ofburner means 104 whereby the vapor generator 102 is heated to initiateproduction of working fluid vapor. The heat from the burner elevates thetemperature of the coils 148 and 150 and the buffer fluid within thespace 152. The coils, the buffer fluid and the working fluid within thetube 150 are all quickly raised to substantially the same temperature.When the temperature in the vapor generator is elevated, the bufferfluid will experience a corresponding pressure elevation. Therefore, thepressure of the buffer fluid may be selected as a means by which thetemperature of the working fluid vapor within the vapor generator ismeasured. Accordingly, the pressure responsive device 156 provides asignal 158 functionally related to the pressure of the buffer fluid andto the temperature of working fluid within the tube 150. This signalconstitutes an input to the siliconcontrolled rectifier 178 in the pumpstarting section 172. For example, when the pressure of the buffer fluidreaches a predetermined level, such as 500 psi, the pressure responsivedevice 156 may operate to provide the input signal to the rectifier 178.The pump starting section 173 is electrically connected to the auxiliarypower source 176 which initially energizes the pump means (131,132).When the rectifier 178 is turned on, current flows from the battery tothe dc winding in the starting motor 182. This, in turn, begins torotate the driveshaft 119 to advance both the expander 116 and the feedpump 132. When current flow to the start-up motor 182 reaches apredetermined level, the current sensitive relay 180 switches on andenergizes the boost pump 131. The boost pump will then supply fluidunder pressure from the reservoir 132 to the feed pump 132. The headsupplied by the boost pump 131 to the feed pump 132 prevents cavitationof the feed pump, therefore the feed pump very quickly begins to supplyworking fluid in the liquid-state to the vapor generator 102 throughlines 134 and 136. Fluid entering the vapor generator 102 is vaporizedand supplied to the throttle valve 112 through lines 106 and 110. Thepumping action of the boost pump 131 and the feed pump 132 continueuntil a predetermined pressure, for example 400 psi, is built up in theline 134. When this occurs, the pressure sensing device 135 terminatesthe inhibiting signal 137 to the adder 192. This permits the valvecontrol means to operate the valve 112 according to the output of thealternator 117. Since the alternator is either not operating at all orbeing driven at a very low level by the starting motor 182, the valvecontrol section 175 opens the valve 112 to substantially the fully openposition. v

The opening of the valve 112 admits vaporized working fluid into theexpander 116. The vaporized working fluid expands and produces workwhich is manifested as a rotational output of the driveshaft 119 and acorresponding electrical output of the alternator 117. The

vapor input to the expander 116 very quickly raises it to the desiredoperating speed, for example 1800 rpm, which is above the speed at whichthe starting motor 182 has been turning the driveshaft 119. As theexpander 116 gains speed, the current flow to the dc winding of thestart-up motor begins to decrease. When the current drops below apresent level, the current sensitive relay will open and deenergize thecentrifugal boost pump 131, which then acts only as a conduit within thesystem. As the expander 116 continues to pick up speed, the current flowto the silicon controlled rectifier 178 will pass a null point and thenthe dc windings will begin to act as a generator and produce a currentflow back to the battery 176, thus tending to charge the battery. Whenthe current flow at the start-up motor reaches zero or reverses, therectifier 178 turns off and is non-conductive. The current output of thestart-up motor is permitted to flow to the battery 176 through the diode179. Operation according to the start-up mode is thus terminated. It canbe seen from the foregoing description, that the elements 178 and 180operate as independently actuable switches and constitute an automaticcoupling means which is operable to initiate and terminate the start-upmode of operation.

The engine 100 continues operating in a selfsustaining manner accordingto the running mode. According to the running mode, the vapor generator102 supplies vaporized working fluid along the line 106, through theseparator 108, and along the lines 110 to the valve 112. The valve 112admits working fluid to the expander. Expansion of the working fluidresults in the output for rotating the shaft 119 to turn the alternator117 and produce an electrical current output. Working fluid is exhaustedfrom the expander 116 through the line 118 to be regenerative heatexchanger 120 where some of the energy stored in the vapor istransferred to working fluid in the liquid state passing through thecoil 121. From the regenerator 120, working fluid passes along the line122 to the condenser 124 where it is liquified and admitted to thereceiver 130. The feed pump 132 operates directly from the expander. Itdrives the liquid working fluid through the heat exchange coil 121 ofthe regenerator 120 and line 136 to the vapor generator 102. Thepressure control valve 140 permits working fluid to return from the line134 to the reservoir 130, if the feed pump 132 is providing an output inexcess of that required by the engine.

The valve control means 175, valve 112, expander 116, and alternator 117operate essentially as a closed loop during the running mode to controlthe valve setting in accordance with the running speed of thealternator. The valve control 175 monitors the output of the alternator117 through the continuous input 188 to the comparator means 190. Theimput 188 is compared to a standard functionally related to the desiredoperating speed of the expander 116. The comparator means provides aninput through the adder means 192 to the pulse generator 194 and leveldetector 196, as described above. This operates stepping motor circuit186 and the stepping motor 184 to variable control the position of thevalve 1 12 to thereby variably control admission of working fluid vaporto the expander. Further, in the running mode, the burner control means162 may be provided with a signal, designated 163, for controlling theoperation of the burner means 104 in accordance with conditions withinthe vapor generator.

The separator 108 removes any lubricant which has entered the workingfluid stream and returns it to a lubricant isolating zone in theexpander 116. The line 129 permits a controlled amount of lubricant topass from the expander to the reservoir when the liquid level in thereservoir is low, as at start-up. A suitable lubricant system isparticularly described in copending and coassigned US. patentapplication Ser. No. 210,749, filed Dec. 22, 1971 in the names of WalterWitzel and Edward Doyle entitled Rankine Cycle Start- Up System.

This preferred embodiment of the invention has been described inconnection with an engine for operating an alternator, in which system aconstant running speed is usually required. In the event of a constantrunning speed being required, the reference to which the comparatorcompares the tachometer signal from the expander is fixed. On theotherhand, this system is equally usable in circumstances wherein a variableoutput engine is required, for example, in an automobile power plant.When a variable speed engine is desired, the reference to which thetachometer signal from the expander 116 is compared is variable. Forexample, it may be variable in accordance with an accelerator position.

Any suitable working fluid, buffer fluid and lubricant may be used inthe above described system, so long as they are compatible with systemcomponents and each other. For example, the working fluid may betrifluoroethanol and water mixture such as Fluoronal 85 manufactured byE. I. du Pont de Nemours & Company, and the buffer fluid may be water.Other examples of working fluids are pure trifluoroethanol, thiophene,and pyridine. Other lubricants may be Sunisco 365 manufactured by SunOil Company, and Humble Therm 500 or Teresso 43 manufactured by HumbleOil Company.

The buffer fluid may be any suitable fluid which will not decompose atthe temperature and pressures encountered.

The above description appears to be characterized by several individualpower sources; the battery 176, the battery 177, the negative voltagesource 133, and a current source for the comparator means 190. All ofthese may be obtained from a single dc power source, numerous powersources being shown in FIG. 1 mainly to simplify the drawing.

This invention contemplates that numerous changes may be made in thesystem described above. Accordingly, several of the preferredembodiments will now be described in connection with FIGS. 3 through 6.

Referencewill first be made to FIG. 3. The engine 10 includes a vaporgenerator 12 associated with a burner means 46. Extending from the vaporgenerator 12 is a line 16 for conducting vaporized working fluid fromthe vapor generator to an expander 18. The expander expands thevaporized working fluid to produce a rotary output of a shaft 20. Fromthe expander 18, the vaporized working fluid is exhausted through a line22 to a regenerative heat exchanger 24. From the regenerative heatexchanger, the working fluid passes through a line 26 to a condensermeans 28. The pump means 30 then draws the condensed working fluid fromthe condenser 28, drives it through the liquid side of the regenerativeheat exchanger 24 and returns it to the vapor generator 12.

A start-up means 32 comprises any conventional start-up motor, such asdc windings 34, a control means 36, the burner means 46, and a pumpingmeans 30 which includes a feed pump 38 and a boost pump 46. The burnermeans 46, the dc windings 34, and the boost pump 40 are connected inelectrical circuit with the control means 36 as shown in FIG. 4. Thecontrol means includes a double-pole single throw switch 50, a currentsensitive relay 52, and a battery means 54. At start-up, the switch 50is closed and energy from the battery means 54 initiates substantiallysimultaneous operation of the burner means 46, the starting motor means34, and the boost pump 40. The burner means is ignited through theswitch 50. The boost pump and starting motor and energized through theswitch 50 and the current sensitive relay 52. The starting motor turnsthe expander 18 and the feed pump 38, while the boost pump 40 suppliesworking fluid in the liquid state from a working fluid retaining zone inthe condenser means 28 to the feed pump 38. The vapor generatorvaporizes the fluid and supplies it to the expander. As the vaporizedworking fluid enters the expander, it begins to op-' erate independentlyof the start-up motor. As the operational speed of the driveshaftincreases, there is a corresponding current reduction in the dc windingsof the start-up motor. When the current drops below a predeterminedlevel, the current sensitive relay 52 will open the connection to theboost pump. The engine will then continue operating in therunning mode.In the running mode, the dc windings act as a generator, but the currentgenerated is below the level required for operating the currentsensitive relay 52 so the boost pump 40 is not reenergized.

FIG. 5 illustrates another embodiment of this invention. The controlmeans is for the embodiment of FIG. 5 designated 36' and illustrated inFIG. 6. Like numerals are used to designate parts like those in FIGS. 3and 4. The control means 36' includes the switch 50, the

battery 54, and the current sensitive relay 52. Interposed between thecurrent sensitive relay and the switch is a silicon controlled rectifier54 capable of receiving a signal from a temperature sensing means 56 inthe vapor generator 12. In parallel with the rectifier 54 is a diode 56.To operate the start-up system, the switch means 50 is closed. First,the battery energizes the burner 46 and the burner raises thetemperature of the vapor generator. When the temperature in the vaporgenerator has reached a predetermined level, the temperature sensingmeans 56 provides an electrical signal to the rectifier 54. Therectifier switches on and permits current to flow along the line 58 tothe start-up motor 34. The current energizes the current sensitive relay52 and thereby initiates operation of the boost pump 40. The system isnow operating according to the start-up mode. Operation of the start-upsystem continues until the working fluid vapor from the vapor generatordrives the expander at a speed sufficient to cause the dc winding in thestart-up motor 34 to provide a current reversal of the type describedabove in connection with FIGS. 1 and 4. As the current flow to the dcwindings drops below a certain predetermined level, the currentsensitive relay 52 cuts off and deenergizes the boost pump 40. When thecurrent actually passes the null point, the current rectifier turns offand is nonconductive in eitherdirection. As the expander 18 rises to andreaches its running speed, the dc windings of the start-up motor willact as generator and charge the battery 54. This battery chargingcurrent is below the level required to deenergize the current sensitiverelay 52.

The diode 56 permits flow of current from the start-up motor to thebattery.

It can be appreciated that this is essentially a twostage start-upsystem in the first stage of which the burner 46 is energized and in thesecond stage of which the start-up motor 34 and the boost pump 40 areenergized. The primary advantage of the system of FIGS. 5 and 6 overthat of FIGS. 3 and 4 is that working fluid in the liquid state isdriven into a preheated vapor generator. Accordingly, a larger volume ofworking fluid may be driven through the vapor generator initially toshorten the time required for the Rankine cycle engine to reach itsrunning mode and achieve shut-down of the start-up system.

The apparatus illustrated in FIG. 5 may, in addition, include valvemeans 60 for controlling admission of vaporized working fluid from thevapor generator 12 to the expander 18 and a control means 62 for thevalve. The control means 62 may be responsive to temperature andpressure sensitive signal producing device 64 and 66, respectively. Thesignal producing devices may be positioned at the outlet of the vaporgenerator. The valve means 60 may be a throttle valve for variablycontrolling the admission of working fluid vapor to the expander or itmay be a valve of the solenoid type which is either opened or closed.Further, the valve means 60 may be expander intake valving. One exampleof such expander intake valving would be the intake valving associatedwith each cylinder of a reciprocating piston expander. The valve means60 and its control 62 could be of the type described in connection withFIG. 1. By way of another example, the valve means 60 may remain closedduring the initial operation in the startup mode and opened only whensufficient temperature and pressure conditions at the outlet of thevapor generator are obtained.

Temperature and pressure sensitive devices for use with this inventionmay be of any convenient type. For example, the temperature sensingdevices may be a thermocouple, a bi-metallic switch, or a thermistor.Examples of suitable pressure sensing devices are a Bourdon tube, apiston and cylinder type pressure switch, or a diaphragmtype pressuresensitive device.

The present invention has been described with reference to variouspreferred embodiments. It should be understood, however, thatmodifications may be made by those skilled in the art without departingfrom the scope of the invention.

We claim:

1. In a closed vapor cycle engine having a vapor generator forvaporizing working fluid, an expander for receiving from said vaporgenerator and expanding vaporized working fluid to produce work, meansfor condensing expanded working fluid vapor, and means for pumpingworking fluid from said condensing means to said vapor generator, anautomatic start-up system comprising:

a. actuator means adapted to communicate with an electrical power sourcemeans; b. electrical meansfor energizing said vapor generator inresponse to operation of said actuator means;

0. valve means for admitting vaporized working fluid from said vaporgenerator to said expander;

d. valve control means for securing said valve means in closed conditionwhen said actuator means is first operated and for thereafterautomatically opening said valve means in response to a predeterminedproduction of working fluid vapor in said vapor generator to supply suchvapor to said expander; and

e. automatic coupling means adapted to communicate with the electricalpower source means for automatically coupling said pumping means andsaid electrical power source means when a predetermined minimumtemperature is produced in said vapor generator to initiate operation ofsaid pumping means and for automatically uncoupling said pumping meansfrom driving relationship with the electrical power source meanssubsequent to the opening of said valve means. I

2. In a closed vapor cycle engine, a start-up system according to claim1 wherein said vapor generator comprises:

a. at least one tubular heat exchange element for conducting workingfluid through said vapor generator; and

b. jacket means concentrically surrounding said heat exchange elementfor containing a thermally stable buffer fluid wherein the pressure ofsaid buffer fluid is functionally related to the temperature of saidworking fluid and wherein said automatic coupling means is responsive tothe pressure of said buffer fluid for coupling said pumping means tosaid electrical power source means.

3. In a closed vapor cycle engine, a start-up system according to claim1 wherein said valve control means is responsive to at least one of thetemperature and pressure conditions of working fluid in said engine.

4. In a closed vapor cycle engine, a start-up system according to claim3 wherein said valve control means is responsive to Working fluidpressure in said engine.

5. In a closed vapor cycle engine, a start-up system according to claim4 wherein said valve control means is responsive to working fluidpressure adjacent the outlet of said pumping means.

6. In a closed vapor cycle engine, a start-up system according to claim3 wherein said valve control means is responsive to at least one of thetemperature and pressure conditions of the working fluid at the outletof the vapor generator.

7. In a closed vapor cycle engine, an automatic startup systemcomprising:

a. a vapor generator for vaporizing working fluid,

having heat source means;

b. expander means in fluid communication with said vapor generator;

c. valve means for selectively prohibiting flow of working fluid fromsaid vapor generator when closed and admitting working fluid from saidvapor generator to said expander means when open.

d. means for supplying working fluid under pressure to said vaporgenerator;

e. first control means for activating said heat source means andinitiating operation of said supplying means;

f. second control means for operating said valve means; and

g. means for prohibiting said second control means from opening saidvalve means subsequent to operation of said first controlmeans foractivating said heat source means an operating said supplying means andthereafter as a function of predetermined conditions in said engine,automatically permitting operation of said second control means to opensaid valve means.

8. In a closed vapor cycle engine, an automatic startup system accordingto claim 7 wherein said second control means opens said valve means toadmit working fluid vapor from said vapor generator to said expanderwhen at least one of predetermined operating temperature and pressureconditions have been attained in said engine.

9. In a closed vapor cycle engine, an automatic startup system accordingto claim 7 wherein said supplying means comprises:

a. means for condensing working fluid vapor exhausted from said expandermeans;

b. pumping means for driving working fluid from said condensing means tosaid vapor generator; and

c. reservoir means for supplying working fluid to said pumping means toprevent cavitation of said pumping means.

10. In a closed vapor cycle engine, an automatic start-up systemaccording to claim 9 wherein said pumping means comprises:

a. a feed pump for directing working fluid to said vapor generator; andI b. a boost pump for drawing working fluid from said reservoir meansand directing it to said feed pump.

11. In a closed vapor cycle engine, an automatic start-up systemaccording to claim 10 wherein said feed pump is driven by said expandermeans and said first control means comprises:

a. means for initiating operation of said boost pump;

and

b. starting motor means for substantially simultaneously advancing saidexpander means and thereby said feed pump.

12. In a closed vapor cycle engine, an automatic start-up systemaccording to claim 10 wherein said control means further comprise meanresponsive to a predetermined operating speed of said expander means fordeenergizing said boost pump.

13. In a closed vapor cycle engine, a start-up system according to claim7 wherein said first control means comprises:

a. first means for activating said heat source means to elevate thetemperature of said vapor generator; and

b. second means for initiating operation of said supplying means as afunction of vapor generator temperature. I

14. In a vapor cycle engine, a start-up system according to claim 13wherein said second control means op erates said valve means to admitworking fluid vapor to said expander means in response to apredetermined working fluid pressure.

15. In a closed vapor cycle engine according to claim 7, a start-upsystem wherein said vapor generator comprises:

a. a tubular working fluid container;

b. a jacket formed about said working fluid container and disposedbetween said working fluid container and said heat' source means;

c. a buffer fluid filling said jacket, whereby heat energy istransferred from said jacket, through said buffer fluid, tosaid workingfluid container;

d. means for activating said heat source means; and

e. means for initiating operation of said supplying means as a functionof buffer fluid pressure, said buffer fluid pressure being functionallyrelated to the temperature of working fluid in said working fluidcontainer.

16. In a vapor cycle engine, a start-up system according to claim 15wherein said second control means operates said valve means to admitworking fluid to said expander means in response to a predeterminedworking fluid pressure. I

17. The apparatus of claim 3 wherein said valve control means opens saidvalve means in response to a predetermined pressure level at the outputof said pumping means.

18. In a closed vapor cycle engine, a start-up system according to claim3 wherein said operating means is responsive to the output of saidexpander.

19. The apparatus according to claim 1 further comprising starting motormeans energizable by said coupling means for initiating operation ofsaid expander.

20. The apparatus of claim 19 wherein said coupling means automaticallyenergizes said starting motor means as a function of vapor generatortemperature.

21. The apparatus of claim 1 wherein said pumping means comprises a feedpump driven during a running mode by a portion of the energy releasedfrom the vastarting motor means energizable by said first switch andadapted to initiate operation of said expander and said feed pump.

23. The apparatus of claim 22 wherein said electrical power source meanscomprises an electrical battery and said starting motor means comprisesan electrical winding linked to the output of said expander and adaptedto operate said expander at a speed below normal operating speed whenenergized by said battery and further adapted to act as an electricalgenerator when said expander'output exceeds said speed below normaloperating speed, further comprising means for conducting electric powergenerated by said starting motor means to said battery for charging saidbattery. =l=

1. In a closed vapor cycle engine having a vapor generator forvaporizing working fluid, an expander for receiving from said vaporgenerator and expanding vaporized working fluid to produce work, meansfor condensing expanded working fluid vapor, and means for pumpingworking fluid from said condensing means to said vapor generator, anautomatic start-up system comprising: a. actuator means adapted tocommunicate with an electrical power source means; b. electrical meansfor energizing said vapor generator in response to operation of saidactuator means; c. valve means for admitting vaporized working fluidfrom said vapor generator to said expander; d. valve control means forsecuring said valve means in closed condition when said actuator meansis first operated and for thereafter automatically opening said valvemeans in response to a predetermined production of working fluid vaporin said vapor generator to supply such vapor to said expander; and e.automatic coupling means adapted to communicate with the electricalpower source means for automatically coupling said pumping means andsaid electrical power source means when a predetermined minimumtemperature is produced in said vapor generator to initiate operation ofsaid pumping means and for automatically uncoupling said pumping meansfrom driving relationship with the electrical power source meanssubsequent to the opening of said valve means.
 2. In a closed vaporcycle engine, a start-up system according to claim 1 wherein said vaporgenerator comprises: a. at least one tubular heat exchange element forconducting working fluid through said vapor generator; and b. jacketmeans concentrically surrounding said heat exchange element forcontaining a thermally stable buffer fluid wherein the pressure of saidbuffer fluid is functionally related to the temperature of said workingfluid and wherein said automatic coupling means is responsive to thepressure of said buffer fluid for coupling said pumping means to saidelectrical power source means.
 3. In a closed vapor cycle engine, astart-up system according to claim 1 wherein said valve control means isresponsive to at least one of the temperature and pressure conditions ofworking fluid in said engine.
 4. In a closed vapor cycle engine, astart-up system according to claim 3 wherein said valve control means isresponsive to working fluid pressure in said engine.
 5. In a closedvapor cycle engine, a start-up system according to claim 4 wherein saidvalve control means is responsive to working fluid pressure adjacent theoutlet of said pumping means.
 6. In a closed vapor cycle engine, astart-up system according to claim 3 wherein said valve control means isresponsive to at least one of the temperature and pressure conditions ofthe working fluid at the outlet of the vapor generator.
 7. In a closedvapor cycle engine, an automatic start-up system comprising: a. a vaporgenerator for vaporizing working fluid, having heat source means; b.expander means in fluid communication with said vapor generator; c.valve means for selectively prohibiting flow of working fluid from saidvapor generator when closed and admitting working fluid from said vaporgenerator to said expander means when open. d. means for supplyingworking fluid under pressure to said vapor generator; e. first controlmeans for activating said heat source means and initiating operation ofsaid supplying means; f. second control means for operating said valvemeans; and g. means for prohibiting said second control means fromopening said valve means subsequent to operation of said first controlmeans for activating said heat source means an operating said supplyingmeans and thereafter as a function of predetermined conditions in Saidengine, automatically permitting operation of said second control meansto open said valve means.
 8. In a closed vapor cycle engine, anautomatic start-up system according to claim 7 wherein said secondcontrol means opens said valve means to admit working fluid vapor fromsaid vapor generator to said expander when at least one of predeterminedoperating temperature and pressure conditions have been attained in saidengine.
 9. In a closed vapor cycle engine, an automatic start-up systemaccording to claim 7 wherein said supplying means comprises: a. meansfor condensing working fluid vapor exhausted from said expander means;b. pumping means for driving working fluid from said condensing means tosaid vapor generator; and c. reservoir means for supplying working fluidto said pumping means to prevent cavitation of said pumping means. 10.In a closed vapor cycle engine, an automatic start-up system accordingto claim 9 wherein said pumping means comprises: a. a feed pump fordirecting working fluid to said vapor generator; and b. a boost pump fordrawing working fluid from said reservoir means and directing it to saidfeed pump.
 11. In a closed vapor cycle engine, an automatic start-upsystem according to claim 10 wherein said feed pump is driven by saidexpander means and said first control means comprises: a. means forinitiating operation of said boost pump; and b. starting motor means forsubstantially simultaneously advancing said expander means and therebysaid feed pump.
 12. In a closed vapor cycle engine, an automaticstart-up system according to claim 10 wherein said control means furthercomprise mean responsive to a predetermined operating speed of saidexpander means for deenergizing said boost pump.
 13. In a closed vaporcycle engine, a start-up system according to claim 7 wherein said firstcontrol means comprises: a. first means for activating said heat sourcemeans to elevate the temperature of said vapor generator; and b. secondmeans for initiating operation of said supplying means as a function ofvapor generator temperature.
 14. In a vapor cycle engine, a start-upsystem according to claim 13 wherein said second control means operatessaid valve means to admit working fluid vapor to said expander means inresponse to a predetermined working fluid pressure.
 15. In a closedvapor cycle engine according to claim 7, a start-up system wherein saidvapor generator comprises: a. a tubular working fluid container; b. ajacket formed about said working fluid container and disposed betweensaid working fluid container and said heat source means; c. a bufferfluid filling said jacket, whereby heat energy is transferred from saidjacket, through said buffer fluid, to said working fluid container; d.means for activating said heat source means; and e. means for initiatingoperation of said supplying means as a function of buffer fluidpressure, said buffer fluid pressure being functionally related to thetemperature of working fluid in said working fluid container.
 16. In avapor cycle engine, a start-up system according to claim 15 wherein saidsecond control means operates said valve means to admit working fluid tosaid expander means in response to a predetermined working fluidpressure.
 17. The apparatus of claim 3 wherein said valve control meansopens said valve means in response to a predetermined pressure level atthe output of said pumping means.
 18. In a closed vapor cycle engine, astart-up system according to claim 3 wherein said operating means isresponsive to the output of said expander.
 19. The apparatus accordingto claim 1 further comprising starting motor means energizable by saidcoupling means for initiating operation of said expander.
 20. Theapparatus of claim 19 wherein said coupling means automaticallyenergizes said starting motor means as a function of vapor generatortemperature.
 21. The apparatus oF claim 1 wherein said pumping meanscomprises a feed pump driven during a running mode by a portion of theenergy released from the vaporized working fluid for directing condensedworking fluid to said vapor generator and a boost pump for drawingcondensed working fluid from said condensing means during a start-upmode and directing it to said feed pump, further comprising a firstswitch for coupling said feed pump to said electrical power source meansin response to the production of a predetermined temperature in saidvapor generator and a second switch responsive to operation of saidfirst switch for coupling said boost pump to said electrical powersource means.
 22. The apparatus of claim 21 further comprising startingmotor means energizable by said first switch and adapted to initiateoperation of said expander and said feed pump.
 23. The apparatus ofclaim 22 wherein said electrical power source means comprises anelectrical battery and said starting motor means comprises an electricalwinding linked to the output of said expander and adapted to operatesaid expander at a speed below normal operating speed when energized bysaid battery and further adapted to act as an electrical generator whensaid expander output exceeds said speed below normal operating speed,further comprising means for conducting electric power generated by saidstarting motor means to said battery for charging said battery.